Anaphylactic Transfusion Reactions Associated with Anti-IgA Antibody

Abstract

A patient had anaphylactic transfusion reactions when transfused with small amounts (10 ml or less) of blood from four consecutive donors. Antibodies to erythrocytes or leukocytes could not be found, but a precipitating antibody reactive with IgA in donor and normal human serum was discovered in the patient's serum. This antibody, which was of the IgG class, fixed complement, and its concentration decreased and then increased after one of the reactions. We postulate that an antigen–antibodycomplement interaction releases kinins that mediate a characteristic anaphylactic reaction. This case illustrates that antibodies reactive with plasma protein antigens should be considered as a cause of transfusion reactions when antibodies to cellular constituents in blood cannot be demonstrated.